The present invention relates to a components feeding apparatus for mounting a multiplicity of types of small components in position on a board at high speed, or more in particularly to a components feeding apparatus for a components mounting machine for mounting a multiplicity of types of very small electronic components stored in a tape reel on a printed board at high speed.
A conventional electronic components mounting machine or apparatus for mounting a multiplicity of types of very small electronic components on a printed board, as disclosed in the U.S. Pat. No. 4,307,832, is so constructed that an electronic components supply unit is disposed on a components feeding table which is laterally reciprocated and adapted to stop at a predetermined position, and the components feeding table is moved each time a transfer head absorbs an electronic component from the feeding unit.
A plan view of this mechanism is shown in FIG. 7. The electronic component mounting mechanism comprises a body base 1, a components feeding table 2, a transfer mechanism using a rotary head or a rectangular coordinates type robot (in FIG. 7, the mechanism 3 uses a rotary head), and an X-Y table 4. A drive mechanism for the components feeding table 2 includes, as shown in FIG. 8 which is a sectional view along line VIII--VIII of FIG. 7, a linear guide 5 with the components feeding table 2 placed thereon, a rack 7, a pinion 8, a reduction gear 9, and a motor 10 for driving the components feeding table 2 through the reduction gear 9 by the rack 7 and pinion 8. Another type of drive mechanism includes a DC motor or stepping motor for driving a ball screw.
Scores to almost a hundred types of tape reel units accommodating electronic components therein are disposed in parallel to each other on the components feeding table 2. This table 2 is positioned at high speed to place any tape reel accommodation the required electronic components just under an absorption point 3a of the transfer mechanism (example rotary head) 3. In synchronism with the absorption of an electronic component and rotation by the transfer mechanism 3, the X-Y table is positioned so that a predetermined point coated with an adhesive of the printed board may come just under the transfer point 3b of the rotary head 3. Then, the electronic component is transferred to the printed board. These steps of operation are performed continuously at high speed.
In this conventional apparatus, the whole apparatus is stopped to supplement the components whenever the electronic components are depleted on the table. For this type of apparatus which transfers as many as several components per second at high speed, this suspension of operation for set-up is a considerable reduction in the working efficiency.
To the extent that the components handled are about 20 to 40 types, the movable units weigh not more than several tens of kg and the motor capacity not more than 1 KW, it is possible to use a controller with a small capacity in this conventional apparatus. However, with an increase in the transfer speed of up to 0.3 to 0.4 seconds per component, and with an increase in the types of components handled to as many as one thousand, with a corresponding increase in the movable units weight to at least 100 kg, the resultant necessary increase in the capacity of the motor and controller make this apparatus uneconomical. Further, if driven by a ball screw, such an apparatus requires a ball screw as long as several meters, thereby rendering a high-speed drive very difficult in technical aspects of control and vibration.
Furthermore, a heavy item weighing more than 100 kg and moving at high speed, generates a great vibration and noise, resulting in various problems of a reduced mounting performance and a reduced strength of component members for a high-precision mounting apparatus.